1. Field of the Invention
The present invention relates to a heat developing apparatus for heating and development of a dry type photosensitive material on which a latent image has been formed owing to exposure, and more particularly to a heat developing apparatus arranged to use a heat developing photosensitive material which contains an inhibitor for inhibiting development.
2. Description of the Related Art
Hitherto, a medical image recording apparatus for use in a digital radiography system, a CT or an MR has been adapted to a wet system with which an image is photographed or recorded on a silver-salt photosensitive material. Then, a wet process is performed to obtain an image. On the other hand, in recent years a dry system heat developing apparatus has attracted attention which does not perform the wet process.
The foregoing heat developing apparatus is arranged to use a heat developing photosensitive material. The heat developing apparatus is arranged to form a latent image on the heat developing photosensitive material by performing exposure corresponding to the image. Then, a heat developing portion of the heat developing apparatus heats and develops the heat developing photosensitive material. Then, the heat developing photosensitive material having the formed image is discharged to the outside of the heat developing apparatus.
The foregoing dry system heat developing apparatus is able to form an image in a time shorter than time required for the wet process. Moreover, the problem of the waste solution process experienced with the wet process can be overcome. Therefore, a need for the heat developing apparatus is expected to be increased.
The density of the heat developing photosensitive material realized during the heat development which is performed by the conventional dry system heat developing apparatus is raised as the heat development temperature is raised and the heat development time is elongated. Therefore, to realize a stable density, the heat development temperature and a period of time in which development is substantially started and the same is completed (substantial heat development time) must precisely be controlled. The substantial heat development time varies owing to an influence of irregularity of the temperature occurring when the temperature of the heat developing photosensitive material is raised or irregularity of the temperature occurring when a cooling process is performed. To meet the above-mentioned requirements and eliminate the influence, it might be considered feasible to employ a structure of the apparatus incorporating a heating means which is a stable heat storage member having a large size.
However, if the heat developing apparatus incorporates the foregoing heat storage member, the overall size of the apparatus cannot be reduced. What is worse, the cost of the apparatus is enlarged excessively. If the precise control of the heat development temperature and the heat development time is not performed, a stable density cannot be realized. Thus, there arises a problem in that irregularity of an image occurs.
In view of the foregoing, an object of the present invention is to provide a heat developing apparatus which is capable of realizing a stable density without a necessity of precisely controlling the heat development temperature and the heat development time so as to prevent image irregularity without enlargement of the size and the cost of the apparatus.